Seasonal variation of Caligus rotundigenitalis infestation on the host fish Etroplus suratensis from the Cochin Backwaters, southwest coast of India

Investigation of four edible fishes (Etroplus suratensis, Oreochromis mossambicus, Lates calcarifer, Chanos chanos) collected from a fish landing center along Cochin Backwaters has done for caligid infestation. Of these, caligids were detected only from Etroplus suratensis and was identified to be Caligus rotundigenitalis. Parasites were attached to the inner side of operculum of host which indicates strong site preference. The annual observation of prevalence, mean intensity and abundance were found to be 19.21%, 1.051 and 0.202 respectively. Variation of prevalence with respect to the different length groups of E. suratensis has discussed in this paper. Damages of the inner side of operculum and increase in mucous production were noticed as a result of copepod attachment.